| Magma mixing in upper mantle: Evidence from high Mg-# olivine hosted melt inclusions in MORBs near East Pacific Rise 13 degrees N | |
| Zhang GuoLiang1,2; Jiang ShaoQing3; Ouyang HeGen1,2; Chen DaiGeng4; Yin XueBo1; Wang XiaoYuan1; Wang XiaoMei1,2; Zeng ZhiGang1 | |
| 2010-06-01 | |
| 发表期刊 | CHINESE SCIENCE BULLETIN
 |
| 卷号 | 55期号:16页码:1643-1656 |
| 文章类型 | Article |
| 摘要 | Early formed high-Mg-# olivine phenocrysts during evolution of MORB magmas usually host melt inclusions, which record importantw information about the early-stage evolution of magma. Five MORB samples from near East Pacific Rise (EPR) 13 degrees N vary little in K/Ti (0.07-0.12), Tb/Lu (1.72-1.84) and Sm/Nd (0.310-0.332) and have similar REEs patterns, indicating that depleted upper mantle has similar mineral composition. Sixty-five initial melt inclusions derived by correcting olivine fractionation and "FeO-Loss" show averagely higher MgO contents than their host rocks. Melt inclusions have higher CaO/Al2O3 ratios than their host rocks, and these CaO/Al2O3 ratios are positively and negatively correlated with MgO and Na2O respectively, suggesting that these magmas have experienced high pressure crystallization of clinopyroxene. Average crystallization pressure, which is calculated based on the pressure dependence of clinopyroxene crystallization, is 0.83 +/- 0.25 GPa, and implys that these melt inclusions are averagely trapped in mantle depth of similar to 24 km. These melt inclusions show negative correlations of Ca-8/Al-8 and Na-8 with Fe-8, and wider ranges of Ca-8/Al-8, Na-8, Fe-8 and K/Ti than their host rocks, suggesting that these melt inclusions formed by mixing magmas of different melting degrees and depths. According to the average value and ranges of Ca-8/Al-8, Na-8, Fe-8 and K/Ti, these magmas would necessitate other mixing ends in shallow crust except in upper mantle. The compositional diversity of melt inclusions in MORBs phenocrysts cannot always be used to indicate magma mixing and crystallization in shallow crust, and melt inclusions in high Mg-# olivine formed under mantle pressure must be excluded in study of the magma process at crustal level. This study shows that, in EPR, MORBs have experienced mixing of magmas formed by different melting degrees and depths in the mantle. |
| 关键词 | Olivine Melt Inclusion Morb Magma Mixing Upper Mantle East Pacific Rise |
| DOI | 10.1007/s11434-010-3051-5 |
| 收录类别 | SCI |
| 语种 | 英语 |
| WOS记录号 | WOS:000278704200012 |
| 引用统计 | |
| 文献类型 | 期刊论文 |
| 条目标识符 | http://ir.qdio.ac.cn/handle/337002/32829 |
| 专题 | 海洋地质与环境重点实验室 |
| 作者单位 | 1.Chinese Acad Sci, Inst Oceanol, Key Lab Marine Geol & Environm, Qingdao 266071, Peoples R China 2.Chinese Acad Sci, Grad Univ, Beijing 100049, Peoples R China 3.Chinese Acad Geol Sci, Beijing 100037, Peoples R China 4.E China Mineral Explorat & Dev Bur, Nanjing 210007, Peoples R China |
| 第一作者单位 | 中国科学院海洋研究所 |
| 推荐引用方式 GB/T 7714 | Zhang GuoLiang,Jiang ShaoQing,Ouyang HeGen,et al. Magma mixing in upper mantle: Evidence from high Mg-# olivine hosted melt inclusions in MORBs near East Pacific Rise 13 degrees N[J]. CHINESE SCIENCE BULLETIN,2010,55(16):1643-1656. |
| APA | Zhang GuoLiang.,Jiang ShaoQing.,Ouyang HeGen.,Chen DaiGeng.,Yin XueBo.,...&Zeng ZhiGang.(2010).Magma mixing in upper mantle: Evidence from high Mg-# olivine hosted melt inclusions in MORBs near East Pacific Rise 13 degrees N.CHINESE SCIENCE BULLETIN,55(16),1643-1656. |
| MLA | Zhang GuoLiang,et al."Magma mixing in upper mantle: Evidence from high Mg-# olivine hosted melt inclusions in MORBs near East Pacific Rise 13 degrees N".CHINESE SCIENCE BULLETIN 55.16(2010):1643-1656. |
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